Apex predators drive top-down effects in ecosystems and the loss of such species can trigger mesopredator release. This ecological process has been well documented in human-modified small areas, but for management and conservation of ecological communities, it is important to know which human factors affect apex predator occurrence and which mediate mesopredators release at large scales. We hypothesized that mesopredators would avoid spatial and temporal overlap with the apex predator, the puma; but that human perturbations (i.e., cattle raising and trophy hunting) would dampen top-down effects and mediate habitat use. We installed 16 camera traps in each of 45, 10 × 10 km grid cells in the Caldén forest region of central Argentina resulting in 706 total stations covering 61,611 km². We used single-season occupancy and two-species co-occurrence models and calculated the species interaction factor (SIF) to explore the contributions of habitat, biotic, and anthropic variables in explaining co-occurrence between carnivore pairs. We also used kernel density estimation techniques to analyze temporal overlap in activity patterns of the carnivore guild. We found that puma habitat use increased with abundance of large prey and with proximity to protected areas. Geoffroy's cats and skunks spatially avoided pumas and this effect was strong and mediated by distance to protected areas and game reserves, but pumas did not influence pampas fox and pampas cat space use. At medium and low levels of puma occupancy, we found evidence of spatial avoidance between three pairs of mesocarnivores. All predators were mostly nocturnal and crepuscular across seasons and mesopredators showed little consistent evidence of changing activity patterns with varying levels of puma occupancy or human interference. We found potential for mesopredator release at large scale, especially on the spatial niche axis. Our results suggest that a combination of interacting factors, in conjunction with habitat features and intervening human activities, may make mesopredator release unlikely or difficult to discern at broad scales. Overall, we believe that promoting the creation of new protected areas linked by small forest patches would likely lead to increased predator and prey abundances, as well as the interactions among carnivores inside and outside of protected areas.

中文翻译：

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在半干旱森林中面对人类干扰评估食肉动物的空间共现和时间重叠

顶级捕食者在生态系统中产生自上而下的影响，而这些物种的丧失会引发中捕食者的释放。这种生态过程已在人类改造的小区域中得到充分记录，但对于生态群落的管理和保护，重要的是要了解哪些人为因素影响顶级捕食者的发生以及哪些介导中捕食者的大规模释放。我们假设中食肉动物会避免与顶级捕食者美洲狮在空间和时间上重叠；但是人类的干扰（即养牛和狩猎战利品）会抑制自上而下的影响并调节栖息地的使用。我们在阿根廷中部的 Caldén 森林地区的 45 个 10 × 10 km 网格单元中的每个网格单元中安装了 16 个摄像头陷阱，从而产生了 706 个总站，覆盖 61,611 km ². 我们使用单季入住和双物种共现模型并计算物种相互作用因子 (SIF) 来探索栖息地、生物和人为变量在解释食肉动物对之间的共现中的贡献。我们还使用核密度估计技术来分析食肉动物行会活动模式的时间重叠。我们发现美洲狮栖息地的使用随着大型猎物的丰富和靠近保护区而增加。Geoffroy 的猫和臭鼬在空间上避开了美洲狮，这种影响很强烈，并且受与保护区和野生动物保护区的距离的影响，但美洲狮不影响潘帕斯狐狸和潘帕斯猫的空间使用。在中等和低水平的美洲狮占有率下，我们发现了三对中食肉动物之间空间回避的证据。所有捕食者大多是夜间和黄昏的，而中捕食者几乎没有一致的证据表明活动模式会随着不同程度的美洲狮占用或人为干扰而发生变化。我们发现了大规模释放中捕食者的潜力，特别是在空间生态位轴上。我们的研究结果表明，相互作用因素的组合，连同栖息地特征和干预人类活动，可能使中捕食者的释放不太可能或难以在大范围内辨别。总体而言，我们认为，促进建立由小片森林斑块连接的新保护区可能会导致捕食者和猎物的丰度增加，以及保护区内外食肉动物之间的相互作用。